Welcome to the 'bolt!
It all depends on your budget, facilities, and severity of the rust. I tore down the body completely and went after everything with a wire cup brush on an angle grinder (keep moving or you'll warp the steel). Then I hosed everything with Rust-Mort (phosphoric acid), washed it down and dried it, and shot primer everywhere before surface rust came back. Most primer is
not going to seal moisture out, so get some paint on it before leaving it in the rain.
Those with better facilities can set up a blast booth and glass bead (sand is not recommended) the body panels; I didn't have that luxury. Those with bigger budgets can have the body "dipped;" also out of my range so I didn't research it too deeply.
Do a search in this forum, and check the Tech Tips link at the top of the page. There are as many approaches to this problem as there are rusty Stovebolts.
